# H04 ```ME 445 – H04
Name _________________________
1) Use complex numbers to plot gain G and phase  as a function of frequency f for the firstorder high-pass RC filter shown below. Plot log10(G) versus log10(f) and plot  in degrees versus
log10(f) over 10 3 Hz  f  10 6 Hz . Attach hard copy of your code.
V in
V out
R = 1.6 M
C = 0.1 F
C
R
G = Vout / Vin
2) Design a simple circuit using small signal diodes and a first-order low-pass filter to convert
the output of an amplified microphone (nominally &plusmn;5V at 100 Hz to 10 KHz ) into a signal that
can be read by an Arduino digital input to determine when sound is present or not. Arduinos
read 0V to 1V as low and 3V to 5V as high. Be certain to provide all component values.
microphone
output
approximate Arduino
digital input
3) Attach the first page of a datasheet for a 1N4002 diode. What is the forward bias voltage
drop for a 1N4002? Would a 1N4002 be viable for part 3) above? Explain your response.

V _______ viable? YES NO (circle one) Why? _______________________________
4) Complete the table below for motor current iM using a collector driven load and an emitter
driven load as shown below. Assume that the power supply has sufficient current capacity. Use
VS = +15V, RM = 8 , Rin = 1K, hFE = 100.
Vin
0V
+1V
+2V
+3V
+4V
+5V
Collector
driven
iM [mA]
Emitter
driven
iM [mA]
Vs
M
Vs
Vin
C
Rin
B
Vin
C
Rin
B
E
M
E
```